I. Field of the Invention
This disclosure relates generally to systems, apparatus and methods for determining a direction, and more particularly to determining a direction, change in distance and/or distance from a camera to a hand making gestures.
II. Background
Many mobile devices today contain a camera to capture images, for example, containing a hand. A standard two-dimensional (2D) camera image provides accurate measurements perpendicular to the camera (referred to here as a plane parallel to the x-axis and y-axis of the camera) but unfortunately little or no information about a perpendicular distance (along the z-axis of the camera) from the camera to the hand. A depth sensor or stereo cameras may provide distance information, thus supplementing a single camera. Other methods estimate an absolute perpendicular distance, usually based upon anatomical models of the hand, but are sensitive to variations in hands between different people, are sensitive to differences in poses and/or require a predefined pose to operate. What is needed is a means to determine a gesture involving a perpendicular distance to a hand using a standard 2D camera image, independently of assumption of a user's hand size and independently of hand pose.